Projection lamp



May 6, 1941.

K. BRENKERT PROJECTION LAMP Filed July 5, 1938 INVENTOR. BY A7271E/FE/Y/rE/Y r ATTORNEY.

Patented May 6, 1941 '2,241,179 PROJECTION LAMP Karl Brenkert, Detroit,Mich, assignor to Brenkert Light Projection Company, Detroit, Mich., acorporation of Michigan I Application July 5, 1938, Serial No. 217,385

4 Claims.

The present invention pertains to improvements in projection lamps.

One of the objects of the invention is to provide a more satisfactorydoor structure for the housing than has hitherto been available. Lamphousings of the general character disclosed herein are provided withdoors for access to the reflector, electrodes and other mechanism in thehousing. The door must extend substantially the entire length of thehousing from front end to rear end for permitting access to the variousinterior parts. It should also, if possible, be of such height as toclear the top of the reflector so that the latter may easily be wiped.

These doors are usually hinged either at one end or at the upper edge.In either case when swung wide open, the door requires a substantialclearance either at the sides or above the top of the housing, as thecase may be. Such-a clearance, however, is not always available in thelimited space within a projection booth. C'onsequently, the opening ofthe doors frequently involves inconvenience to the operator, 2.compromise in the proper construction for operation of the door, or thenecessity of moving other apparatus out of the way when opening thedoor.

The present invention overcomes these difficulties and at the same timeenables a full door opening without requiring excessive space at thesides or over the top of the housing. To effect this purpose, the dooris constructed in two sections hinged together along a line longitudinalof the housing, the upper end of the section being hinged to the housingat the upper edge of the door opening. A guide link joins the firsthinge axis to an end wall of the housing and forms a toggle with thelower section. The link determines the path of the door in itsmovements, and the toggle constitutes a means for locking the door inopen or closed position without the use of latches or the like. In thefull open position of the door, the sections stand above the dooropening but adjacent or opposite to one another, having swung relativelyon their Figure l is aperspective view of the device, with the doorsopen;

Figure 2 is a vertical section of the door;

Figure 3 is an enlarged detail; and Figure 4 is a side elevation withthe door panels omitted.

Reference to these views will now be made by use of like characterswhich are employed to designate corresponding parts throughout.

In Figure 1 is shown a projection lamp housing having a base I and frontand end walls 2 and 3 respectively. The end walls are joined across thetop by a roof 4, the complete design of the housing being shown in theUnited States Design Patent of Henry M. Horldt, No. 111,602, of October1938. Substantial openings are thus provided between the end walls, onboth sides of the housing. These openings are normally covered by doorsof the construction presently to be described. The end walls 2 and 3 aresubstantially circular, and the base I and roof 4 are of substantiallyequal width. This width may be determined from Figure 2 which shows theangular extent of one of the doors. Since both doors are alike, only oneneed be described.

Across the top of the side opening, a hinge rod 5 is mounted in the endwalls 2 and 3, slightly below the adjacent edge of the roof 4. From theends of the rod 5, are suspended a pair of curved door frame members 6having the same radius of curvature as the end walls. Each member 6,when in its downward position; extends slightly below the horizontalcenter of the side opening, as shown in Figure 2. The lower end of eachmember 6 is formed with an inwardly extending hinge knuckle 1.

Another hinge rod 8 is passed through the knuckles 1 and supportsanother pair of curved door frame members 9 depending therefrom byknuckles III at their upper ends. The latter also extend inwardly, whilethe members 9 form a continuation of'the members 6 on the same radius.Adjacent knuckles are formed with fiat faces H which abut each otherwhen the door is in the closed or lowered position shown in Figure 2,for a purpose that will presently be described. One of the faces llreceives a set screw l2 locked by a nut l3 and engaging in a recess M inthe opposite face, for taking up manufacturing tolerances in theconstruction of the door assembly.

The upper face I I engages either the lower face or the set screw l2 sothat the weight of the upper door section bears on the lower section,holding the door firmly closed by preventing the lower section fromswinging out. A tie rod l is passed through the lower ends of the member9 to complete the frame structure. Grooves I! are formed in the endwalls 2 and 3, as clearly shown in Figures 1 and 4.

Across each pair of opposed frame members 6 and 9 is laid and secured asheet metal or other suitable door panel I8 adapted to fill thecorresponding portion of the opening. These members extend beyond theouter edges and ends of their supporting frame members to enter thegrooves l1 and cover the upper and lower margins of the opening when thedoor is in the dropped or closed position shown in Figure 2.

Pivot posts of the end walls 2 and 3 at points approximately verticallyabove the edges of the base I or the.

rods l5 when the latter are in their lowermost position. A guide link 20extends from each end of each rod l5 to the post IS on the same side ofthe vertical axis of the nearer wall Each of the lower panels 18' hasahandle 2| 'near its lower edge. To open the door, the

handle is pulled upward and outward,-whereupon the rod I5 follows anarcuate path on the radius of links 29. The mutual engagement of thefaces H prevents the lower section from swinging outward independentlyof the upper section. Consequently, as the handle is pulledupward, bothdoor sections rise together, the upper section hinging on the rod 5 andthe lower section on rod 8, with increasing separation of the knuckles1, '10. I

The upper section precedes the lower section in reaching the full openposition. Near the endof the movement, the rod I5 crosses the line Adrawn through the pivot l9 and the hinge rod 8 in the full open positionof the latter. When the line is crossed, the weight of the mass aids incompleting the opening movement. The result of this action is that thedoor is held in its open position by its own weight, without the use oflatches orsimilar devices.

The link 20 and adjacent member 9 may be regarded as a toggle. When theintermediate point E5 of the toggle crosses the line A, or the axis ofalinement of the toggle, the weight of the door throws the intermediatepoint further in the same direction or to the locking position as i1-lustrated. In this position the link 20 holds the rod .8 spaced from theend walls and consequently supports some of the weight of the door.

The lamp housing contains projection'mechanism including a reflector 22.The construction of the door is such that, when in open position,

it clears the top of the reflector, permitting access thereto forcleaning or other purposes, without reaching under the door. By virtueof the folding action of the door, reflector is cleared without bringingthe door too high above the housing or too far laterally of the housing,as would be the case with a rigid door. Maintaining the door withincomparatively small space limits, during opening and closing, isimportant in view of the limited space in a projection booth andobstructing objects that may be positioned near the top and sides of thehousing.

The absence of latches for holding the door open is also important.Latches frequently fail, or operators neglect to use them when workinghurriedly, as a result of which the door is liable.

to fall on the arm of the operator and cause a serious injury since thedoor has considerable weight.

Although a specific embodiment of the inven- I9 extend inwardly fromeach I tion has been illustrated and described, it will be understoodthat various alterations in the details of construction may be madewithout departing from the scope of the invention, as indicated by theappended claims.

What I claim is:

1. In combination with a housing, a suspended door comprising a sectionhinged at its upper horizontal edge to said housing, another sectionhinged to the lower horizontal edge of the first section and adapted. tofold against the first section in open position, and a link hinged tothe opposite and free edge of the second section and to said housing ata point between said free edge and the first hinge axis, said link andsecond section constituting a toggle when both sections are in openposition, the first hinge aXis lying at one side of the axis ofalinement of said toggle, and the free edge or intermediate toggle pivotbeing adapted to pass to the same side of the axis of alinement from theother side thereof in the opening movement of the door, whereby theweight of the door holds the door open.

2. In combination with a housing, a suspend ed door comprising a sectionhinged at its upper horizontal edge to said housing, another sectionhinged to the lower horizontal edge of the first section and adapted tofold against the first section in open position, and a link hinged tothe opposite and free edge of the second section and to said housing ata point between said free edge and the first hinge axis, said link andsecond section constituting a toggle when both sections are in openposition, the first hinge axis lying at one side of the axis ofalinement of said toggle, and the free edge or intermediate toggle pivotbeing adapted to pass to the same side of the axis of alinement from theother side thereof in the opening movement of the door, whereby theweight of the door holds the door open, the second section beingslightly shorter than the first section, whereby said free edge clearsthe first hinge axis in the open position of the door.

3. In combination with a housing, a suspended door comprising a sectionhinged at its upper horizontal edge to said housing, another sectionhinged to the lower horizontal edge of the first section and adapted tofold against the first section in open position, and a link hinged tothe opposite and free edge of the second section and to said housing ata point between said free edge and the first hinge axis, said link andsecond section constituting a toggle when both sections are in openposition, said sections being curved in continuation of each otheroutwardly of said housing, with said link and point lying on the concaveside thereof, the first hinge axis lying at one side of the axis ofalinement of said toggle, and the free edge or intermediate toggle pivotbeing adapted to pass to the same side of the axis of alinement from theother side thereof in the opening movement of the door, whereby theweight of the door holds the door open.

4. In a projection lamp housing having a reflector therein and a lateralopeningadapted to expose substantially the full height of saidrefiector, a suspended door comprising a section hinged at its upperhorizontal edge to said housing at the upper edge of said opening,another section hinged to the lower horizontal edge of the first sectionand adapted to fold against the first section in open position, and alink hinged to the opposite and free edge of the second section and tosaid housing at a point between said free edge and the first hinge axis,said linkand second section constituting a toggle when both sections arein open position, the first hinge axis lying at one side of the axis ofalinement of said toggle, and the free edge or intermediate toggle pivotbeing adapted to pass to the same side of the axis of alinement from theother side thereof in the opening movement of the door, whereby theweight of the door holds the door open, said second section being ofsuch length that the free edge takes a position at approximately thelevel of the first hinge axis in the open position of the door.

KARL BRENKERT.

